US4322622A - Device for the achromatic magnetic deflection of a beam of charged particles and an irradiation apparatus using such a device - Google Patents

Device for the achromatic magnetic deflection of a beam of charged particles and an irradiation apparatus using such a device Download PDF

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Publication number
US4322622A
US4322622A US06/136,820 US13682080A US4322622A US 4322622 A US4322622 A US 4322622A US 13682080 A US13682080 A US 13682080A US 4322622 A US4322622 A US 4322622A
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United States
Prior art keywords
magnetic
particles
sectors
deflection device
sector
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Expired - Lifetime
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US06/136,820
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English (en)
Inventor
Dominique Tronc
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CGR MEV SA
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CGR MEV SA
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    • G—PHYSICS
    • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
    • G21K—TECHNIQUES FOR HANDLING PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
    • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
    • G21K1/08—Deviation, concentration or focusing of the beam by electric or magnetic means
    • G21K1/093—Deviation, concentration or focusing of the beam by electric or magnetic means by magnetic means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J49/00—Particle spectrometers or separator tubes
    • H01J49/02—Details
    • H01J49/20—Magnetic deflection
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N5/00—Radiation therapy
    • A61N5/10—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy
    • A61N2005/1085—X-ray therapy; Gamma-ray therapy; Particle-irradiation therapy characterised by the type of particles applied to the patient
    • A61N2005/1089—Electrons

Definitions

  • the present invention relates to an achromatic magnetic deflection device for deflecting by an angle ⁇ a beam of charged accelerated particles (electrons for example), these particles being able to present a large range of moments of quantities of movement.
  • the deflection device of the invention enables in particular a beam of electrons accelerated between 10 and 20 Mev for example to be deflected by an angle ⁇ > ⁇ , without having to modify the values of the magnetic fields created in the air gaps of the pole pieces forming part of the deflection device.
  • It is an object of the invention to provide a device for the achromatic magnetic deflection of a beam of accelerated charged particles comprising at least one electromagnet having pole pieces delimiting air gaps in which are created magnetic fields having the same direction and specific values so that the paths of the particles have the form of loops whose lengths depend on the momentum of the particles, these pole pieces delimiting a first, a second and a third magnetic sector disposed one after the other and joined together, the whole of these magnetic sectors having a plane of symmetry perpendicular to the plane of the mean path of the beam of particles and intersecting this plane along an axis XX, the magnetic deflection device presenting successively to the beam of particles a flat input face, a first curved face, a second curved face and a flat output face, the input and output flat faces forming therebetween an angle 2 ⁇ , the first and second curved faces, as well as the axis of symmetry XX, being substantially orthogonal to the different paths of the particles, the values of the magnetic inductions
  • FIG. 1 shows a first embodiment of a magnetic deflection device according to the invention.
  • FIG. 2 shows the paths of the particles in the embodiment of FIG. 1.
  • FIG. 3 shows a second embodiment of a magnetic deflection device according to the invention.
  • FIG. 4 shows the paths of the particles in the device of FIG. 3.
  • FIGS. 5 and 6 show respectively the variation of the ratio K of the radii of curvature of the different paths for the embodiments shown in FIGS. 1 and 3.
  • FIGS. 7 and 8 show respectively a top view and a sectional view along the axis of symmetry XX of a pair of pole pieces used in the device of the invention.
  • FIG. 9 shows the lens effect obtained in the horizontal plane with the devices of FIGS. 2 and 3.
  • FIGS. 10 and 11 show respectively a variation of the device of the invention and the lens effects of this device on the beam, in the horizontal and vertical planes.
  • the magnetic sector M 1 is delimited by a flat input face E and a face F 1 substantially circular in shape, with a radius of curvature R
  • the magnetic sector M 3 is delimited by a flat output face S and a face F 2 identical to face F 1 and the intermediate contiguous magnetic sector M 2 being delimited by faces F 1 and F 2 .
  • FIG. 2 shows the paths t 1 , t 2 and t 3 of the particles having respectively an energy E 1 , E 2 , E 3 .
  • the path t 1 has a center of curvature C 1 in magnetic sector M 1 and a center of curvature C 2 in magnetic sector M 2 .
  • This path t 1 is orthogonal on the one hand to faces F 1 , F 2 and to the axis of symmetry XX of the device.
  • the center of curvature C 2 of the paths in magnetic sector M 2 must be situated on the axis of symmetry XX of the deflection device.
  • This center of curvature C 2 of the paths may be defined, in an orthonormed plane xy, such as shown in FIG. 2, by the relationships:
  • r 1 being the radius of curvature of the paths in magnetic sector M 1 (and in magnetic sector M 3 not shown) and r 2 being the radius of curvature of the paths in magnetic sector M 2 .
  • FIG. 3 shows another embodiment of a magnetic deflection device in accordance with the invention for deflecting the incident beam f i by an angle 2 ⁇ equal to 240°, this deflection being achromatic.
  • This magnetic deflection device comprises an electromagnet having magnetic coils (not shown) and provided with a pair of pole pieces of a shape and dimensions such that they delimit three contiguous magnetic sectors M 10 , M 20 , M 30 .
  • Magnetic sector M 10 presents to the beam a flat input face E and a face S 10 having the form of an arc of a circle with radius R 10
  • magnetic sector M 30 has a flat output face S and a face S 20 identical to face S 10
  • magnetic sector M 20 contiguous to magnetic sectors M 10 , M 30 is delimited by faces S 10 and S 20 .
  • the heights of the air gaps of magnetic sectors M 10 , M 20 and M 30 are such that the magnetic inductions created in each of these sectors are respectively equal to KB o , B o and KB o .
  • FIG. 4 shows in detail the different paths of the particles having different momentum in the deflection device shown in FIG. 3.
  • the ratio b/R has been chosen equal to 0.63, b being the distance separating the mean path of incident beam f i from point I, the intersection of axis XX with the input face E of the deflection device.
  • the centers of curvature C 2 in magnetic sector M 20 are substantially placed on the axis of symmetry XX.
  • These different paths t 10 , t 20 . . . correspond to energy particles respectively equal to E 10 , E 20 , E 30 , E 40 .
  • pole piece A 1 in accordance with the invention and the magnetic coil which is associated therewith.
  • Pole piece A 1 circular in shape, is formed by an element a 1 (FIG. 8) made from magnetic material, soft iron for example, whose dimensions are defined by the operating characteristics of the deflection device (type of particles, energy of these latter, value of the magnetic inductions used), and by an element c 1 superimposed on element a 1 and fixed to this latter by means of three screws v 1 , v 2 , v 3 for example, this element c 1 delimiting the intermediate magnetic sector M 2 (or M 20 ).
  • element a 1 shown in FIG. 7 there is shown an embodiment of a pole piece A 1 in accordance with the invention and the magnetic coil which is associated therewith.
  • Pole piece A 1 circular in shape, is formed by an element a 1 (FIG. 8) made from magnetic material, soft iron for example, whose dimensions are defined by the operating characteristics of the deflection device (type of particles, energy of these latter, value of the magnetic inductions used),
  • the thicknesses of elements a 1 and c 1 are chosen with respect to the value of the magnetic inductions used in magnetic sectors M 1 , M 2 , M 3 (or M 10 , M 20 , M 30 ) so as to avoid any saturation of the magnetic material forming pole piece A 1 .
  • An annular magnetic coil b 1 is disposed on pole piece A 1 .
  • Opposite pole piece A 1 is placed an identical pole piece A 2 , associated with the annular magnetic coil b 2 identical to b 1 (FIG. 8).
  • the different paths of the particles converge in the horizontal plane H in a focus F H situated on the output face S of the third magnetic sector M 3 (FIG. 9) whereas in the vertical plane V, the whole of the deflection device behaves like a creeping space.
  • a stigmatic magnetic deflection system i.e. for forming a pinpoint image of an object point situated outside the axis of the incident beam f i
  • the divergences of the beam must be compensated for both in the vertical plane V and the horizontal plane H.
  • FIG. 9 shows the lens effects obtained with a magnetic deflection device whose input E and output S faces are orthogonal to the mean path of the beam of particles.
  • FIG. 11 shows the action of the magnetic lenses formed by the magnetic deflection device of the invention, shown in FIG. 10, when this deflection device presents to the beam an input face E forming an angle a little different from ⁇ /2 with the mean path of this incident beam f i .
  • the beam f i is subjected to focusing both in the horizontal plane H and in the vertical plane V, this double focusing being situated at a distance l from the output face S of the deflection device, this distance l corresponding for example to the distance separating the output face S of the deflecton device and a target Q intended to be bombarded by a substantially pinpoint beam.
  • the construction of the intermediate magnetic sector M 2 may be different from the examples given. It may in particular form a separate element which will be joined to the end sectors M 1 , M 3 (or M 10 , M 30 ).
  • the magnetic deflection device of the invention presents several advantages. It is compact and simple to construct. Furthermore, it has a wide passband. It may be advantageously used in radiotherapy apparatus, doing away with the need to adjust the magnetic field for a wide energy range of particles.

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  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Biomedical Technology (AREA)
  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Engineering & Computer Science (AREA)
  • Pathology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Radiology & Medical Imaging (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • High Energy & Nuclear Physics (AREA)
  • General Health & Medical Sciences (AREA)
  • Public Health (AREA)
  • Veterinary Medicine (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Particle Accelerators (AREA)
  • Radiation-Therapy Devices (AREA)
US06/136,820 1979-04-03 1980-04-03 Device for the achromatic magnetic deflection of a beam of charged particles and an irradiation apparatus using such a device Expired - Lifetime US4322622A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR7908370 1979-04-03
FR7908370A FR2453492A1 (fr) 1979-04-03 1979-04-03 Dispositif de deviation magnetique achromatique d'un faisceau de particules chargees et appareil d'irradiation utilisant un tel dispositif

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US4322622A true US4322622A (en) 1982-03-30

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US06/136,820 Expired - Lifetime US4322622A (en) 1979-04-03 1980-04-03 Device for the achromatic magnetic deflection of a beam of charged particles and an irradiation apparatus using such a device

Country Status (6)

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US (1) US4322622A (enrdf_load_stackoverflow)
EP (1) EP0018247B1 (enrdf_load_stackoverflow)
JP (1) JPS55163499A (enrdf_load_stackoverflow)
CA (1) CA1152232A (enrdf_load_stackoverflow)
DE (1) DE3067922D1 (enrdf_load_stackoverflow)
FR (1) FR2453492A1 (enrdf_load_stackoverflow)

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4425506A (en) 1981-11-19 1984-01-10 Varian Associates, Inc. Stepped gap achromatic bending magnet
US4716468A (en) * 1985-04-24 1987-12-29 Hitachi, Ltd. Apparatus for controlling the electron beam in a television camera tube
US4760261A (en) * 1985-09-13 1988-07-26 Carl-Zeiss Stiftung Alpha-type electron energy filter
US5049755A (en) * 1988-01-22 1991-09-17 Stenbacka Rolf Method and apparatus for the treatment of surfaces of machine components
US5412283A (en) * 1991-07-23 1995-05-02 Cgr Mev Proton accelerator using a travelling wave with magnetic coupling
US5449914A (en) * 1993-03-26 1995-09-12 Carl-Zeiss-Stiftung Imaging electron energy filter
US6066852A (en) * 1994-07-15 2000-05-23 Hitachi, Ltd. Electron energy filter
US20100127169A1 (en) * 2008-11-24 2010-05-27 Varian Medical Systems, Inc. Compact, interleaved radiation sources

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4455489A (en) * 1981-11-19 1984-06-19 Varian Associates, Inc. Quadrupole singlet focusing for achromatic parallel-to-parallel devices
DE3929475A1 (de) * 1989-09-05 1991-03-14 Balzers Hochvakuum Verfahren und vorrichtung zur umlenkung eines strahls
WO2015197521A1 (de) 2014-06-24 2015-12-30 Covestro Deutschland Ag Verfahren zur herstellung von nitrobenzol

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3967225A (en) * 1974-08-15 1976-06-29 Atomic Energy Of Canada Limited Magnetic beam deflector system
US4006422A (en) * 1974-08-01 1977-02-01 Atomic Energy Of Canada Limited Double pass linear accelerator operating in a standing wave mode
US4191887A (en) * 1978-03-29 1980-03-04 Varian Associates, Inc. Magnetic beam deflection system free of chromatic and geometric aberrations of second order
US4243916A (en) * 1978-04-21 1981-01-06 C.G.R.Mev Magnetic mirror for beams of charged particles accelerated in an accelerator

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2058485A1 (enrdf_load_stackoverflow) * 1969-09-10 1971-05-28 Thomson Csf
GB1463001A (en) * 1973-01-22 1977-02-02 Varian Associates Achromatic magnetic beam deflection system

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4006422A (en) * 1974-08-01 1977-02-01 Atomic Energy Of Canada Limited Double pass linear accelerator operating in a standing wave mode
US3967225A (en) * 1974-08-15 1976-06-29 Atomic Energy Of Canada Limited Magnetic beam deflector system
US4191887A (en) * 1978-03-29 1980-03-04 Varian Associates, Inc. Magnetic beam deflection system free of chromatic and geometric aberrations of second order
US4243916A (en) * 1978-04-21 1981-01-06 C.G.R.Mev Magnetic mirror for beams of charged particles accelerated in an accelerator

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4425506A (en) 1981-11-19 1984-01-10 Varian Associates, Inc. Stepped gap achromatic bending magnet
US4716468A (en) * 1985-04-24 1987-12-29 Hitachi, Ltd. Apparatus for controlling the electron beam in a television camera tube
US4760261A (en) * 1985-09-13 1988-07-26 Carl-Zeiss Stiftung Alpha-type electron energy filter
US5049755A (en) * 1988-01-22 1991-09-17 Stenbacka Rolf Method and apparatus for the treatment of surfaces of machine components
US5412283A (en) * 1991-07-23 1995-05-02 Cgr Mev Proton accelerator using a travelling wave with magnetic coupling
US5449914A (en) * 1993-03-26 1995-09-12 Carl-Zeiss-Stiftung Imaging electron energy filter
US6066852A (en) * 1994-07-15 2000-05-23 Hitachi, Ltd. Electron energy filter
US20100127169A1 (en) * 2008-11-24 2010-05-27 Varian Medical Systems, Inc. Compact, interleaved radiation sources
US8198587B2 (en) 2008-11-24 2012-06-12 Varian Medical Systems, Inc. Compact, interleaved radiation sources
US8779398B2 (en) 2008-11-24 2014-07-15 Varian Medical Systems, Inc. Compact, interleaved radiation sources
US9746581B2 (en) 2008-11-24 2017-08-29 Varex Imaging Corporation Compact, interleaved radiation sources

Also Published As

Publication number Publication date
EP0018247A2 (fr) 1980-10-29
EP0018247B1 (fr) 1984-05-23
DE3067922D1 (en) 1984-06-28
EP0018247A3 (en) 1980-11-12
FR2453492B1 (enrdf_load_stackoverflow) 1982-04-30
CA1152232A (en) 1983-08-16
JPS55163499A (en) 1980-12-19
JPS6333120B2 (enrdf_load_stackoverflow) 1988-07-04
FR2453492A1 (fr) 1980-10-31

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